Tape applicator

ABSTRACT

The invention relates to a tape applicator for a tape of the type having one side of adhesive material and the other side of heat stable material. The applicator comprises a roller, heating means in the roller for heating the roller surface, and means for applying the heat stable surface of the tape upon the surface of the roller. The roller is mounted on an arm pivotally mounted in a frame which is slidably mounted. The roller rests upon a sheet supporting surface and a counterweight is connected to the arm for adjusting the pressure of the roller upon the sheet.

United States Patent PATENTE-inflow lfm 3617.422

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SHEET 2 UF 2 PATENT ACI N TAPE APPLICATOR BACKGROUND OF THE INVENTION l.Field of the Invention The invention is in the field of tape structures,particularly those of weftless filament type, and of method andapparatus for adhesively applying such a tape to containers, packages,and the like 2. Description of the Prior Art Weftless filament tapes andtheir production are the subject of many prior art patents.

Tapes of various kinds are in widespread use as 1. reinforcement orclosure means for containers, particularly those of paperboard orcorrugated board type, wherein the tape is employed to retain closureflaps in closed position, and 2. as opening means for such containers,wherein the tape is appropriately positioned on the container andemployed as a tear strip. Such tapes must possess adequate strength forthe purpose and must also incorporate therein an adhesive layer toprovide an effective bond to the container wall surface. lt is, ofcourse, desirable that, for practical use of such a tape, its cost ofmanufacture be as low as possible and that it be capable of applicationin a convenient and trouble-free manner. However, tapes of satisfactorystrength are usually of such relatively high cost that their use isrestricted to special circumstances. Moreover, the step of applying thetape is frequently attended by difficulties such as troublesome transferof adhesive from the adhesive layer to surfaces of the applicator or thelike.

SUMMARY OF THE INVENTION An essential feature of the tape in accordancewith the present invention is that it has a longitudinally extendingsurface coating section that has a surface contact adhesioncharacteristic at temperatures at which the remaining coating section isheat stable. Such surface contact adhesion characteristic is not ofpressure sensitive type but rather requires the application of heat torender the surface coating section adhesive when applied to anothersurface.

Such a tape may be applied by an applicator having a heated surfacearranged to soften only the one coating section whereby when suchcoating section of the tape is engaged with another surface the tapewill be adhesively applied to such other surface.

The tape applicator ofthe present invention broadly comprises a roller,a heating element in the roller for heating the peripheral surfacethereof, and means for directing a length of tape onto the peripheralsurface of the roller.

The invention also resides in a method of applying the tape of theinvention to sheet material which comprises applying heat to theheat-stable section of the tape for transmission through the tape to theadhesive section and softening thereof, and then applying theheat-softened section to the sheet material.

Brief Description of the Drawing FIG. l is a cross section, on a greatlyenlarged scale, of a tape in accordance with the invention,

FIG. 2 is a partial edge elevation ofthe tape of FIG. 1,

FIG. 3 is a cross section, also on an enlarged scale, of a modified formof tape,

FIG 4 is a side elevation ofa tape applying device, and

FIG. 5 is an end elevation, partly in section, of the device of FIG. 4.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS Referring to FIGS. l and 2,indicates a tape in accordance with the invention which comprises twolayers l1 and l2.

Layer 1l comprises a plurality of elongated fibrous threads or strandsor filaments 13. Filaments 13 extend longitudinally of thc tupe and maybe of cotton, rayon, polyester, polyamide,

or other synthetic or natural fibers of strands. They are embedded in asynthetic resin material such as polymerized vinyl chloride, celluloseacetate,methyl methacrylate, polystyrene, and the like, which is stableat temperatures exceeding about 200 F., and below about -20 F.

Layer 12 consists of a hot-melt adhesive bonded adhesively to layer 11.Hot-melt adhesives are now recognized as a specific class of adhesives.They may comprise a low molecular weight natural or synthetic wax orresin, such as coumarone-indene resins; mineral, vegetable and petroleumwaxes; alkyds; terpene and phenol-formaldehyde resins. This lowmolecular weight base material is reinforced and strengthened with ahigh molecular weight polymer such as ethyl cellulose, polyvinylacetate, polyethylene, polystyrene, polyamide and the like. They areheat-stable at temperatures below about F. and soften to an adhesiveconsistency at temperatures of about 250-350 F.

Referring to FIG. 3, a strand of strip composed of rows of filaments 43are arranged in tape configuration with the individual filaments insubstantially directed contact with adjoining filaments.

A heat barrier coating or layer 44 is applied directly to one sidesurface of the strip, such coating being adhered directly to thefilaments which become partially embedded therein. The coating may becomposed of any suitable heat-stable composition, such as that employedin layer l1 of FIG. l.

A hot-melt adhesive coating or layer 45 is applied directly to the otherside surface of the strip, such coating being also adhered directly tothe filaments which become partially em bedded therein.

There is thus formed a tape having approximately half of itslongitudinal surface extent constituted by one layer 44 and the otherhalf of such longitudinal surface constituted by the layer 45.

Referring to FIGS. 4 and 5, the applicator shown comprises supportingframe generally indicated at I4 which may be mounted for adjustablesliding movement, by means ofa guide l5, on a horizontal rail 16. Asshown, adjustment may be effected by a rack 17 on the rail, a gear 18meshing with the rack and fixed to a shaft 19 journaled in the guide anddriven by a hand wheel 20.

A plate 21 fixed to the guide 15 has pivoted thereto at 22 an arm 23.Fixed to the free end portion of arm 23 is a spindle 24 on which isjournaled a free-running roller 25. Roller 25 has a smooth peripheralsurface 26 which is heated in any suitable manner. As shown, the heatingmeans comprises an electrical resistance element 27 housed in a chamber28 adjoining the peripheral wall 29. Power supply means for the elementincludes a cable 30 connected to a power source, a connector 31 having apair of brushes 32 in contact with a pair of contact rings 33 carried bythe roller hub 34, and connections (not shown) connecting the rings 33with the resistance element.

The roller, through its peripheral surface 26, is arranged to rest upona sheet 35 of corrugated board, paperboard or the like (for subsequentuse as a container wall), such sheet 35 being disposed upon any suitablesupporting surface 36. The sheet 35 is adapted to be moved along thesurface 36 in any suitable manner in the direction of the arrow, suchmovement resulting in rotation of the roller 25. The pressure exerted bythe roller on the sheet 35 may be adjustably controlled by means of anadjustable counterweight 37 mounted on a rod 38 fixed to arm 23.

A length of tape such as 10 is fed to the applicator from any suitablesource of supply in such manner that a section thereof is in contactwith a major portion of the peripheral surface 26 of the roller. Asshown, the tape is fed over free-running rollers 39 and 40 mounted onbrackets 41 and 42 carried by the frame 14 whereby it is fed onto anupwardly travelling portion of surface 26 and thence along thedownwardly travelling portion of surface 26 until it comes into contactwith the surface portion of sheet 35 upon which the roller rests. Thus,in the modification shown, the tape will be in contact with aboutthree-quarters of the length of surface 26.

The tape l is fed onto roller surface 26 with the surface of layer l1 incontact therewith whereby the surface of layer 12 will be brought intocontact with sheet 35. Surface 26 is heated by the heating meansdescribed to a degree only suffi cient to render layer l2 adhesive andtherefore without affecting the stability of layer ll. Ordinarily, thesurface 26 will be heated to a temperature in the range of 200 F, to 400F., for example, about 300 I".

It will be apparent, therefore, that on contact of the softened adhesivelayer l2 with sheet 35, the tape l0 will adhere thereto. Moreover,movement of the sheet 35 as previously indicated will also act toprovide a continuous feed of tape thereon.

Since the hot-melt adhesive layer l2 comes in contact with no surfaceofthe applicator, there is no undesirable transfer of softened adhesiveto parts thereof. In other words, heat transfer to the layer l2 iseffected through the heat-stable layer ll. Moreover, the heat-stablelayer ll imparts to the tape a tensile strength that is at least severaltimes that of a tape composed solely of a hot-melt adhesive,

lt will be apparent that the diameter of roller 25 will be such that itscircumference will have an extent chosen to provide a particular dwelltime of the tape thereon, such dwell time being substantially onlysufficient to render the layer 12 adhe sively bondable to the sheet 35.An example of a satisfactory diameter is about 18 inches.

The tape of FIG. 3 may, of course, be applied by the applicator in thesame manner as tape 10.

It will also be apparent that the dimensions of the tape will vary inaccordance with its conditions of use. Obviously, its width may varywithin wide limits. lts thickness will also be variable but an exampleof a satisfactory tape l0 for standard use is about 0.008 inch, layer llhaving a thickness of 0.005 inch and layer 12 having a thickness of0.003 inch.

l. A tape applicator comprising a supportingvframe, an arm pivotallymounted in said frame, a roller rotatably mounted on said arm and havinga tape engageable peripheral surface, a heating element in said rollerfor heating said surface, means for directing a length of tape onto saidsurface, a sheet-supporting surface, said roller having its peripheralsurface resting upon said surface, and counterweight means connected tosaid arm for adjusting the pressure of said roller on saidsheet-supporting surface.

2. A tape applicator as defined in claim l, including a guide rail, aguide fixed yto said frame and slidable along said rail, and means foradjusting the position of said frame and applicator on said rail.

3. A tape applicator as dened in claim 2, including tape guiding rollersmounted on said frame for guiding tape onto said peripheral surface.

' a: e u s

2. A tape applicator as defined in claim 1, including a guide rail, aguide fixed to said frame and slidable along said rail, and means foradjusting the position of said frame and applicator on said rail.
 3. Atape applicator as defined in claim 2, including tape guiding rollersmounted on said frame for guiding tape onto said peripheral surface.